Book Description

The reaction between ZrC and F2 was investigated at 278 to 410 deg C, using 31 mm HgF/syb 2/. The reaction was found to be linear with time, and linear rate constants were computed. The activation energy was determined to be 22.1 plus or minus 1.6 kcal/mole. ZrB2 is not attacked by 31 mm HgF2 below 500 deg C. The weight losses from reaction of ZrB2 with F2 at 600 to 900 deg C and of ZrC with F2 at 700 to 950 deg C, were rneasured for a F2 pressure of 2.7 mm Hg. Zero-time linear rate constants were calculated and found not to be strongly temperature-dependent above 600 deg C, and the activation energies are essentially zero for both ZrB2 and ZrC. For ZrC at 350 deg C and for ZrB2 at 700 deg C, the rate is approximately proportional to the square root of F2 partial pressure, while for ZrC at 700 deg C, it is proportional to the 1.5 power of F2 partial pressure. (D.L.C.).